Measurement temperature, the minimum memory/maximum temperature value. High temperature alarm (the temperature exceeds the preset value will emit sound alarm), low temperature alarm (the temperature is lower than the preset value will emit sound alert). Indoor temperature range:0C -+60C Outdoor temperature range:-40C -+60C Temperature accuracy:+/- 1.0 Power (host):2 x AAA battery(Not included) Power (sub-machine):2 x AA battery (Not included) Wireless range:100 meters without interference. warn: Do not install anti -battery positive and negative poles. Avoid direct rain in wireless transmitters. If the sensor signal connection is interrupted, long press the key to remove the button for 3 seconds to restore the signal connection. How to install outdoor sensors: Note: In order to receive the real temperature value, the sensor should be avoided directly in the sun. We suggest that the remote sensor is installed of the outdoor north. Before installing , book a screw, leave 5 mm from the screw head, and install the outdoor sensor on the screw. The electronic part of the outdoor sensor has a layer of moisture -proof synthetic resin to protect the circuit. However, the sensor is not waterproof, so it should be avoided directly rain. Sub-machine Quantity:B:2PCS Colour:As Shown Material:Plastic Package Contents: 1 * host machine 2 * sub-machine Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.